1-.DELTA..sup.9 -Tetrahydrocannabinol (THC) is the most psychoactive constituent of the marihuana plant (Cannabis sativa). The use of marihuana can result in euphoria, hallucinations, sedation and temporal distortion. Its widespread abuse has prompted a need to monitor the use. THC is metabolized to a variety of psychoactive and inactive derivatives and the majority of the metabolites are excreted in the urine as glucuronides (Life Sci. 17, 1637 (1975), Res. Comm. Chem. Path. Pharm. 17, 421 (1977) and Clin. Pharm. Ther. 34, 352 (1983)).
The preparation of antibodies to THC metabolites requires the synthesis of a THC derivative in order to covalently attach the derivative to an antigenic polypeptide or protein. In addition, the THC derivative is covalently attached to various polypeptides, proteins or labels for use in screening antibodies and in the immunoassay process. The THC derivative should mimic the structure of the THC metabolite sought to be measured. Therefore, the selection and synthesis of the types of THC derivatives for covalent attachment to proteins, polypeptides or labels is critical. In addition, the THC derivatives need to be stable and soluble in an aqueous solution.
THC compounds and conjugates for immunization and immunoassay have been described in U.S. Pat. Nos. 4,833,073 and Euro. Pat. Appl. No. 279,308.